Current Topics in Chemistry - Bruice

Dr. Glaser's "Chemistry is in the News"
To Accompany Bruice, Organic Chemistry, 3/e.
Chapter 13. NMR Spectroscopy.

For each of the following questions, please refer to the following article:

BILINGUALISM COMES IN DIFFERENT WAYS
by Dolores Kong (Boston Globe, July 10, 1997)

Editorial Comments

I grew up in Germany and did not learn English until I was a teenager. Having lived in the US for some fifteen years, I am pretty much bilingual by now. My daughter most likely will grow up to be bilingual in English and German since her Mommy speaks English with her and the proud Papa frequently speaks German to her. Yet, according to the Boston Globe article there will be a significant difference in the kind of bilingual capacities of the two of us: My daughter and I will process the two languages differently in our "neuronal Broca's areas".

My point is simply that we humans now have the ability to look inside the brain and learn how the brain works by direct observation! What a totally breath-taking idea! The next century might well turn out to be the century of cognitive psychology, that is, the business of investigating intelligence. Take a look at the programs in cognitive psychology at Michigan, Rutgers, Johns Hopkins University, and The University of Pittsburgh to get an idea of the activities in this exciting field. The CNBC web site at Pittsburgh also features a large compendium of resources on cognitive neuroscience around the world. And "functional magnetic resonance imaging" (fMRI) is one of the key methods that enables a direct observation of the brain at work.

What is MRI or Magnetic Resonance Imaging? On the web site of The MRI Center, of Woburn, Mass., one can read that "MRI, or Magnetic Resonance Imaging, is the fastest and safest way to get the clearest pictures of the human anatomy. This advanced technology uses magnetic field and radio waves to access the inner workings of the body. The pictures produced by MRI help the physician to clearly and accurately detect and define the differences between healthy and diseased tissues." The procedure is rather patient friendly and, in fact, there are now MRI compatible Audio/Video Systems, that allow patients to watch their favorite TV program or video tape during an MRI procedure and audio headsets are available to decreases the noise and to permitting two-way communication between the technologist and patient.

How does MRI work? Dr. Hornak of Rochester Institute of Technology, has created an outstanding website on The Basics of MRI. Take a look at Dr. Hornak's site and "open" the "large monitor" option. Read the introduction to learn about the chemical basics of MRI. In particular, I want you to take a look at the section "Microscopic Property Responsible for MRI" and click on the little squares in that text section. You may also enjoy browsing around in the imaging sections to view some actual MRI images.

Now that we know how MRI scans are taken and what physical principle they are based on, the step to "functional MRI" -- or fMRI -- is easy. A website by the National Institutes of Health on fMRI explains that fMRI provides a picture of the brain's ever changing activity rather than its static structure. This is accomplished by tracking brain blood flow. The more active a brain area is the more blood flows to it. Thus, fMRI can provide a moment-by-moment movie of brain activity.

Pertinent Text References
Chapter 13. NMR Spectroscopy.

Questions

Question 1: How does the activity in Broca's region differ in people that grew up bilingual as compared to people that acquired a second language later in life?

Answer 1: Among those who grew up bilingual, activity was noted in the same region of the part of the brain known as Broca's area. But among those who learned a second language later, activity was noted in separate parts of the Broca's area, one for the native language, one for the later language.

Question 2: Explain the physical basis of MRI. Be sure to use as much NMR terminology as possible and realize what the similarities and differences are between NMR and MRI.

Answer 2: H-NMR and MRI both are hydrogen nuclear magnetic resonance spectroscopies, that is, a probe containing H-atoms is placed in a magnetic field and radio wave absorptions are measured. The big difference is that we measure total absorption only in NMR spectrosocopy while in MRI the absorption is measured as a function of location.

Question 3: Explain in simple terms the principle of fMRI.

Answer 3: See editorial comments and links provided.

Question 4: What are the principal areas of research conducted with fMRI?

Answer 4: Mental functions and mental disease.

Chemistry and Society.
Question 5: The new technique of fMRI has made a lot of headlines over the past few years. And that is well deserved. Yet, one should also realize that the method remains rather "crude" when it comes to applications in cognitive psychology. All that is viewed is "activity" as measured by "blood flow". This might create situations of overinterpretations and abuses of the results of the method. Discuss.